This is a Human Performance Heuristics Wiki. I collected a number of "rules of thumb" regarding human limits needs and capabilities for role-playing games (GURPS). A lot of performance heuristics come from Safety Protocols, Athletics, Fitness, Diet and Nutrition, and Military Performance and Operational Standards.
I found these all useful in taking care of both my mental and physical well being. It also made me aware of key emotional and energy level indicators (by energy I mean fatigue and optimal performance levels).

Given that this is a collection of Models, Hypothesis and Heuristics there should be some clarity on what basic underlying principle is there that attempts to make this scientific.

Economics of Resources - everything has a trade-off, but not all trade-offs are equal. These trade-offs have marginal benefits and penalties. Ideally the Heuristic or Models developed try to simplify this to something easy to remember or use.

There should be credible cited sources - It gives everyone else the opportunity to devise a better model/heuristic. The wiki is a big place, it can accomodate a lot of different takes and interpretations of data.

Athletic Life-Style - A Conservative Average or the most Consistent level of Performance

Diet -

Body Mass Index - Height and Weight constituted BMI, but it is Diet, Exercise and Physique

Work and Stress Levels - With Heart Rate and Blood Pressure one can plot the average and amount of Stress one gets regularly per week. Journalizing helps also relieve stress levels as well as keep track of their frequency, intensity, and possibly duration.